Table 1.
Characteristics of the study population in the Northern Finland Birth Cohort 1986 and the Generation R Study, the Netherlands
| NFBC 1986 (n = 8330) | Generation R (n = 7586) | |||
| n | Mean (SD) or n (%) | n | Mean (SD) or n (%) | |
| Offspring | ||||
| Sex | 8330 | 7586 | ||
| Male | 4259 (51.1%) | 3823 (50.4%) | ||
| Female | 4070 (48.9%) | 3763 (49.6%) | ||
| Birth weight (g) | 8330 | 3547 (549) | 7586 | 3461 (497) |
| Gestational age (weeks) | 8330 | 39.8 (1.8) | 7586 | 39.9 (1.8) |
| Maternal biological measures | ||||
| Pre-pregnancy BMI (kg/m2) | 8330 | 21.6 (3.7) | 7586 | 22.7 (4.4) |
| End pregnancy BMI (kg/m2) | 8300 | 26.8 (4.3) | 7586 | 26.7 (5.3) |
| Systolic blood pressure at 20 weeks (mm Hg) | 8129 | 120 (15) | 7063 | 116.6 (12) |
| Diastolic blood pressure at 20 weeks (mm Hg) | 8129 | 70 (12) | 7063 | 66 (12) |
| Systolic blood pressure at 30–36 weeks (mm Hg) | 8129 | 125 (12) | 7063 | 117 (16) |
| Diastolic blood pressure at 30–36 weeks (mm Hg) | 8129 | 80 (15) | 7063 | 60 (9) |
| Haemoglobin at first visit (g/dL) | 8129 | 13.6 (1.1) | 6477 | 12.1 (1.0) |
| Maternal psychosocial§ measures | ||||
| House ownership | 7447 | 6038 | ||
| Yes | 4119 (55.3%) | 3215 (53.3%) | ||
| No | 3328 (44.7%) | 2823 (46.8%) | ||
| Marital status | 8234 | 6924 | ||
| Married/co-habitating | 7877 (95.7%) | 5900 (85.2%) | ||
| Unmarried/widowed/divorced | 357 (4.3%) | 1024 (14.8%) | ||
| Maternal age (years) | 8330 | 27.7 (5.5) | 7581 | 29.5 (5.3) |
| Maternal alcohol use | 7901 | 6563 | ||
| Yes | 979 (12.4%) | 2366 (36.1%) | ||
| No | 6922 (87.6%) | 4197 (63.9%) | ||
| Maternal education | 7184 | 7256 | ||
| Tertiary | 1899 (26.4%) | 2933 (40.4%) | ||
| Secondary | 4713 (65.6%) | 3453 (47.6%) | ||
| Basic | 572 (8.0%) | 870 (12.0%) | ||
| Maternal employment | 7234 | 5751 | ||
| Employed | 5132 (70.9%) | 4122 (71.7%) | ||
| Unemployed | 2102 (29.1%) | 1629 (28.3%) | ||
| Pregnancy desirability* | 7098 | 2285 | ||
| Yes | 6494 (91.6%) | 2174 (95.1%) | ||
| No | 598 (8.4%) | 111 (4.9%) | ||
| Maternal smoking during pregnancy | 7239 | 6653 | ||
| Yes | 608 (8.4%) | 1251 (18.8%) | ||
| No | 6631 (91.6%) | 5402 (81.2%) | ||
| Maternal working position | 6296 | 5671 | ||
| Sitting | 4841 (76.8%) | 3472 (61.2%) | ||
| Standing or walking | 1455 (23.1%) | 2199 (38.8%) | ||
| Parity | 8060 | 7908 | ||
| Nulliparous | 2643 (32.8%) | 4480 (56.7%) | ||
| Multiparous | 5417 (67.2%) | 3428 (43.4%) | ||
| Previous pregnancy complications† | 8287 | 4209 | ||
| Yes | 1676 (20.2%) | 1355 (32.2) | ||
| No | 6611 (79.8%) | 2854 (67.8%) | ||
| Ethnicity | 8330 | 7172 | ||
| Finnish | 8330 (100%) | – | ||
| European‡ | – | 4501 (53.3%) | ||
| Non-European | – | 3949 (46.7%) | ||
| Paternal measures | ||||
| Paternal BMI (kg/m2) | 7832 | 23.7 (3.3) | 25.0 (4.4) | |
| Paternal employment | 7137 | 4396 | ||
| Employed | 5739 (80.4%) | 4003 (91.1%) | ||
| Unemployed | 1398 (19.6%) | 393 (8.9%) | ||
| Paternal smoking | 7286 | 3169 | ||
| Yes | 2847 (39.1%) | 1951 (44.2%) | ||
| No | 4439 (60.9%) | 2466 (55.8%) | ||
| Paternal alcohol use | 6997 | 4450 | ||
| Yes | 4977 (71.1%) | 3672 (82.5%) | ||
| No | 2020 (28.9%) | 778 (17.5%) | ||
Values are mean (SD) for continuous normally distributed and percentages for categorical variables.
*Pregnancy desirability has been defined in NFBC1986 by the question—‘Is the current pregnancy wanted?’ and in Generation R by the question—‘How do you feel about your current pregnancy?’ and the responses were—‘Happy’, ‘Normal’ and ‘Not happy.’ The data were harmonised between two cohorts and the responses ‘Happy’ and ‘Normal’ were included into category ‘Yes’ and ‘Not Happy’ into ‘No’.
†Previous pregnancy complications included miscarriages and stillbirths.
‡In Generation R, European included participants with ethnicity as Dutch, American Western or other Europeans.
§Psychosocial is an umbrella term, used as surrogate for some of the possible social and psychological measures.
BMI, body mass index; NFBC1986, Northern Finland Birth Cohort 1986.